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dc.contributor.authorSilberstein, Susana
dc.contributor.authorSchlenstedt, Gabriel
dc.contributor.authorSilver, Pam A.
dc.contributor.authorGilmore, Reid
dc.date2022-08-11T08:10:05.000
dc.date.accessioned2022-08-23T16:54:54Z
dc.date.available2022-08-23T16:54:54Z
dc.date.issued1998-11-17
dc.date.submitted2008-08-15
dc.identifier.citationJ Cell Biol. 1998 Nov 16;143(4):921-33.
dc.identifier.issn0021-9525 (Print)
dc.identifier.pmid9817751
dc.identifier.urihttp://hdl.handle.net/20.500.14038/42606
dc.description.abstractMembers of the eukaryotic heat shock protein 70 family (Hsp70s) are regulated by protein cofactors that contain domains homologous to bacterial DnaJ. Of the three DnaJ homologues in the yeast rough endoplasmic reticulum (RER; Scj1p, Sec63p, and Jem1p), Scj1p is most closely related to DnaJ, hence it is a probable cofactor for Kar2p, the major Hsp70 in the yeast RER. However, the physiological role of Scj1p has remained obscure due to the lack of an obvious defect in Kar2p-mediated pathways in scj1 null mutants. Here, we show that the Deltascj1 mutant is hypersensitive to tunicamycin or mutations that reduce N-linked glycosylation of proteins. Although maturation of glycosylated carboxypeptidase Y occurs with wild-type kinetics in Deltascj1 cells, the transport rate for an unglycosylated mutant carboxypeptidase Y (CPY) is markedly reduced. Loss of Scj1p induces the unfolded protein response pathway, and results in a cell wall defect when combined with an oligosaccharyltransferase mutation. The combined loss of both Scj1p and Jem1p exaggerates the sensitivity to hypoglycosylation stress, leads to further induction of the unfolded protein response pathway, and drastically delays maturation of an unglycosylated reporter protein in the RER. We propose that the major role for Scj1p is to cooperate with Kar2p to mediate maturation of proteins in the RER lumen.
dc.language.isoen_US
dc.relation<a href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=pubmed&cmd=Retrieve&list_uids=9817751&dopt=Abstract">Link to Article in PubMed</a>
dc.subjectAlleles
dc.subjectChaperonins
dc.subjectEndoplasmic Reticulum
dc.subjectFungal Proteins
dc.subjectGene Expression Regulation, Fungal
dc.subjectGlycosylation
dc.subjectHSP40 Heat-Shock Proteins
dc.subjectHSP70 Heat-Shock Proteins
dc.subjectHeat-Shock Proteins
dc.subjectMembrane Proteins
dc.subjectMutagenesis
dc.subjectOligosaccharides
dc.subjectOxidative Stress
dc.subjectProtein Folding
dc.subjectRNA, Messenger
dc.subject*Saccharomyces cerevisiae Proteins
dc.subjectTemperature
dc.subjectYeasts
dc.subjectBiochemistry
dc.subjectCell Biology
dc.subjectMolecular Biology
dc.subjectPharmacology
dc.titleA role for the DnaJ homologue Scj1p in protein folding in the yeast endoplasmic reticulum
dc.typeArticle
dc.source.journaltitleThe Journal of cell biology
dc.source.volume143
dc.source.issue4
dc.identifier.legacyfulltexthttps://escholarship.umassmed.edu/cgi/viewcontent.cgi?article=1938&amp;context=oapubs&amp;unstamped=1
dc.identifier.legacycoverpagehttps://escholarship.umassmed.edu/oapubs/939
dc.identifier.contextkey579829
refterms.dateFOA2022-08-23T16:54:55Z
html.description.abstract<p>Members of the eukaryotic heat shock protein 70 family (Hsp70s) are regulated by protein cofactors that contain domains homologous to bacterial DnaJ. Of the three DnaJ homologues in the yeast rough endoplasmic reticulum (RER; Scj1p, Sec63p, and Jem1p), Scj1p is most closely related to DnaJ, hence it is a probable cofactor for Kar2p, the major Hsp70 in the yeast RER. However, the physiological role of Scj1p has remained obscure due to the lack of an obvious defect in Kar2p-mediated pathways in scj1 null mutants. Here, we show that the Deltascj1 mutant is hypersensitive to tunicamycin or mutations that reduce N-linked glycosylation of proteins. Although maturation of glycosylated carboxypeptidase Y occurs with wild-type kinetics in Deltascj1 cells, the transport rate for an unglycosylated mutant carboxypeptidase Y (CPY) is markedly reduced. Loss of Scj1p induces the unfolded protein response pathway, and results in a cell wall defect when combined with an oligosaccharyltransferase mutation. The combined loss of both Scj1p and Jem1p exaggerates the sensitivity to hypoglycosylation stress, leads to further induction of the unfolded protein response pathway, and drastically delays maturation of an unglycosylated reporter protein in the RER. We propose that the major role for Scj1p is to cooperate with Kar2p to mediate maturation of proteins in the RER lumen.</p>
dc.identifier.submissionpathoapubs/939
dc.contributor.departmentDepartment of Biochemistry and Molecular Pharmacology
dc.contributor.departmentDepartment of Biochemistry and Molecular Biology
dc.source.pages921-33


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